Comparison of effects of standard diuretics and indanone in isolated toad cornea and bladder

Short-circuit current (SCC) techniques were used to monitor effects of various diuretic agents on Na+ transport in toad bladder and Cl- transport in toad cornea. In bladder, various agents from different "classes" of diuretics inhibited SCC whereas in cornea only "loop diuretics," i.e., those with a primary site of action in the ascending limb of the loop of Henle, inhibited SCC. Classification of the diuretics based on sensitivity in cornea and bladder revealed that diuretics with a common renal site of action gravitated into common classification groups. Thus, our studies suggested that cornea may be a suitable model of the thick ascending limb of the loop of Henle and that cornea and bladder, studied jointly, may serve as an in vitro system for predicting potential renal sites of action of new diuretics. This system, when used to characterize the new diuretic indanone, revealed that this agent, in all respects, displayed the characteristics of a loop diuretic.